Multidimensional liquid chromatography: a breakthrough in the assessment of physiological vitamin K levels.

Owing to the lack of sensitivity and/or selectivity of the existing chemical assays, vitamin K deficiency has always been diagnosed indirectly by measuring its effect on blood coagulation. We used our recently developed multidimensional liquid chromatographic assay for what is, to the best of our knowledge, the first systematic investigation of physiological vitamin K levels in human blood. It allowed the unequivocal demonstration of trans-phylloquinone (vitamin K1) and its quantification down to a level of 0.5 nanogram per milliliter of serum (ng/ml. In healthy adults, a mean serum concentration of 2.6 ng/ml was found, with a normal range of 0.9 to 7.8 ng/ml. These values apparently are distributed in a log-normal way.